**2.1 Biogas to the grid**

When the biogas finally had been produced, treated und conditioned it will either be fed into a nearby gas pipeline system or grid or it will be burned and transformed into electric power which is fed into the electric grid. In the following chapters we review and discuss the aspects of the gas grid, only.

Normally, the gas grid used by biogas plants will be a low or medium pressure operated distribution network. Certain conditions may require that the biogas is compressed to a higher level and being fed into a high pressure transportation network.

Gas Quality Parameter Computation in Intermeshed Networks 137

Fig. 2. Total load/feed-in (blue), industrial (RLM) and small consumer load (red) vs. time

In certain areas the biogas feed-in in the network is in wintertime only a small percentage and the area of influence is therefore small, too; but it is large in summertime. This fact principally leads to problems in pipeline connection, operation, constant gas quality delivery and fair billing (see below, Operational Aspects). In the future – when the number of plants and/or biogas production will increase - we will expect a considerable higher

The gas used in the networks for the final customer has to fulfill quality and composition requirements. According to the standard defined by DVGW G 260 working sheet two main types of natural gas (gas families) are distinguished which stem from different

Aside from the composition of the gas, for technical reasons the values of calorific value and Wobbe-Index are important characteristics. A typical range of these values is used in

(hours) of a big city

0

20.09.04

30.09.04

10.10.04

20.10.04

30.10.04

09.11.04

19.11.04

29.11.04

09.12.04

19.12.04

29.12.04

08.01.05

18.01.05

28.01.05

07.02.05

17.02.05

27.02.05

09.03.05

19.03.05

29.03.05

08.04.05

18.04.05

28.04.05

**Datum**

08.05.05

18.05.05

28.05.05

07.06.05

17.06.05

27.06.05

07.07.05

17.07.05

27.07.05

06.08.05

16.08.05

26.08.05

05.09.05

15.09.05

25.09.05

05.10.05

15.10.05

25.10.05

04.11.05

14.11.05

24.11.05

2.000.000

4.000.000

6.000.000

**Einspeisung / Abgabe**

8.000.000

10.000.000

impact on network operation and surveillance tasks.

**3. Basic methods of the gas mixing process** 

sources and production locations:

**3.1 Gas parameters, gas quality figures (G 260, G 685)** 

• H-Gas, high calorific value (Russian source, typically) • L-Gas, low calorific value (North Sea source, mainly)

practice and will be permanently measured and surveyed:

Typical locations of biogas plants and the major cities the corresponding gas transportation and distribution network are shown in figure 1.

Fig. 1. Biogas plant locations in Germany 2011 (source: DENA)
